A novel two‐dimensional cadmium(II) complex: poly[diaquatris(μ 4 ‐cyclohexane‐1,4‐dicarboxylato)bis[2‐(pyridin‐4‐yl)‐1 H ‐benzimidazole]tricadmium(II)

The title compound, [Cd 3 (C 8 H 10 O 4 ) 3 (C 12 H 9 N 3 ) 2 (H 2 O) 2 ] n or [Cd 3 (chdc) 3 (4‐PyBIm) 2 (H 2 O) 2 ] n , was synthesized hydrothermally from the reaction of Cd(CH 3 COO) 2 ·2H 2 O with 2‐(pyridin‐4‐yl)‐1 H ‐benzimidazole (4‐PyBIm) and cyclohexane‐1,4‐dicarboxylic acid (1,4‐chdcH 2 ). The asymmetric unit consists of one and a half Cd II cations, one 4‐PyBIm ligand, one and a half 1,4‐chdc 2− ligands and one coordinated water molecule. The central Cd II cation, located on an inversion centre, is coordinated by six carboxylate O atoms from six 1,4‐chdc 2− ligands to complete an elongated octahedral coordination geometry. The two terminal rotationally symmetric Cd II cations each exhibits a distorted pentagonal–bipyramidal geometry, coordinated by one N atom from 4‐PyBIm, five O atoms from three 1,4‐chdc 2− ligands and one O atom from an aqua ligand. The 1,4‐chdc 2− ligands possess two conformations, i.e. e , e ‐ trans ‐chdc 2− and e , a ‐ cis ‐chdc 2− . The cis ‐1,4‐chdc 2− ligands bridge the Cd II cations to form a trinuclear {Cd 3 }‐based chain along the b axis, while the trans ‐1,4‐chdc 2− ligands further link adjacent one‐dimensional chains to construct an interesting two‐dimensional network.